Cylon is an acronym for Cybernetic Life-form Node. It was designed by Graystone Industries as a combat robot. The first prototypes lacked adequate artificial intelligence for combat, but with the installation of the meta-cognitive processor in a U-87, along with data from Zoe Graystone's sentient avatar, one prototype excelled at this function. ("Pilot")
After the successful elimination of the terrorist threat at Atlas Arena, Cylons become widely used, especially in low-qualified professions. Cylons are still considered things (from the Cylon perspective – they are treated as slaves). Most of the Cylons have converted to Monotheism - in the extreme form of the STO. ("Apotheosis") These circumstances lead to the First Cylon War and to the Fall of the Twelve Colonies.